Heretic|Scripting: Scripted touch action for special things

A Thing definition may specify an "On touch" script that gets run when the thing is touched. This replaces any hardcoded logic that might have affected the thing.

See the manual for an example: https://manual.dengine.net/ded/thing#on_touch

IssueID #2352

doomsday/apps/libdoomsday/src/defs/dedparser.cpp

@@ -1262,6 +1262,9 @@ DENG2_PIMPL(DEDParser)
                     RV_INT_ELEM("Misc2", (*mo)["misc"], 1)
                     RV_INT_ELEM("Misc3", (*mo)["misc"], 2)
                     RV_INT_ELEM("Misc4", (*mo)["misc"], 3)
+
+                    RV_STR("On touch", (*mo)["onTouch"]) // script function (MF_SPECIAL)
+
                     RV_END
                     CHECKSC;
                 }

doomsday/apps/libdoomsday/src/defs/thing.cpp

@@ -43,6 +43,7 @@ void Thing::resetToDefaults()
     def().addNumber("height", 0);
     def().addNumber("mass", 0);
     def().addNumber("damage", 0);
+    def().addText  ("onTouch", ""); // script function to call when touching a special thing
     def().addArray ("flags").array().addMany(NUM_MOBJ_FLAGS, 0);
     def().addArray ("misc").array().addMany(NUM_MOBJ_MISC, 0);
 }

doomsday/apps/plugins/common/include/mobj.h

@@ -228,6 +228,27 @@ mobj_t *Mobj_LaunchMissile (mobj_t *mob, mobj_t *missile, coord_t const targetPo
 
 void Mobj_InflictDamage(mobj_t *mob, mobj_t const *inflictor, int damage);
 
+enum mobjtouchresult_e {
+    MTR_UNDEFINED,
+    MTR_KEEP,
+    MTR_MAKE_DORMANT,
+    MTR_HIDE,
+    MTR_DESTROY
+};
+
+/**
+ * Called when @a toucher comes into contact with special thing @a special that has a
+ * custom scripted touch action.
+ *
+ * @param mob      Thing doing the touching.
+ * @param special  Special thing being touched.
+ * @param result   What to do with the special thing afterwards.
+ *
+ * @return @c true if a scripted action is defined for the object. In this case, @a result
+ * will contain a valid value afterwards.
+ */
+dd_bool Mobj_TouchSpecialScriptedThing(mobj_t *mob, mobj_t *special, enum mobjtouchresult_e *result);
+
 #ifdef __cplusplus
 }  // extern "C"
 

doomsday/apps/plugins/common/src/world/mobj.cpp

@@ -28,6 +28,7 @@
 #include <doomsday/world/mobjthinkerdata.h>
 #include <de/String>
 #include <de/mathutil.h>
+#include <de/Log>
 #include <QTextStream>
 
 #include "dmu_lib.h"
@@ -1152,3 +1153,65 @@ void Mobj_RestoreObjectState(mobj_t *mob, de::Info::BlockElement const &state)
     }
     #endif
 }
+
+dd_bool Mobj_TouchSpecialScriptedThing(mobj_t *mob, mobj_t *special, enum mobjtouchresult_e *result)
+{
+    using namespace de;
+
+    // Check Thing definition for an onTouch script.
+    const auto &thingDef = DED_Definitions()->things[special->type];
+    if (const String onTouchSrc = thingDef.gets(QStringLiteral("onTouch")))
+    {
+        LOG_AS("Mobj_TouchSpecialScriptedThing");
+
+        const auto &self = THINKER_DATA(special->thinker, ThinkerData).objectNamespace();
+
+        // We will make it seem like the special thing has a script function
+        // called "onTouch", even though we are only now parsing the script from
+        // the DEDs. In the future, there might be an actual "onTouch" function in
+        // some Thing class that gets called instead (in this case, the Thing
+        // definition would be created in a script and not via DED).
+        //
+        // The function will perform any actions required for the touch interaction.
+        // "self" points to the special thing, "toucher" is given as argument to
+        // the function. The function returns a code that tells what to do with the
+        // special item afterwards: "keep", "dormant", "hide", "destroy".
+
+        String src = "def onTouch(toucher)\n";
+        src += onTouchSrc;
+        src += "\nend";
+
+        Record ns;
+        Script script(src);
+        Process proc(&ns);
+        proc.run(script);
+        proc.execute();
+
+        // Function is ready, call it now with the mobjs.
+        ns.add(QStringLiteral("self")).set(new RecordValue(self));
+        std::unique_ptr<Value> resultValue(
+            Process::scriptCall(Process::TakeResult,
+                                ns,
+                                QStringLiteral("onTouch"),
+                                &THINKER_DATA(mob->thinker, ThinkerData)));
+        if (result)
+        {
+            *result = MTR_KEEP;
+            if (resultValue && !is<NoneValue>(resultValue.get()))
+            {
+                const String val = resultValue->asText();
+                if      (val == "keep")    *result = MTR_KEEP;
+                else if (val == "dormant") *result = MTR_MAKE_DORMANT;
+                else if (val == "hide")    *result = MTR_HIDE;
+                else if (val == "destroy") *result = MTR_DESTROY;
+                else
+                {
+                    LOG_SCR_ERROR("Invalid return value from function: \"%s\"")
+                        << resultValue->asText();
+                }
+            }
+        }
+        return true;
+    }
+    return false;
+}

doomsday/apps/plugins/heretic/src/p_inter.c

@@ -511,6 +511,7 @@ typedef enum {
     IT_ITEM_TORCH,
     IT_ITEM_FIREBOMB,
     IT_ITEM_TELEPORT,
+    IT_ITEM_CUSTOM, // scripted
     IT_AMMO_WAND,
     IT_AMMO_WAND_LARGE,
     IT_AMMO_MACE,
@@ -953,6 +954,7 @@ void P_TouchSpecialMobj(mobj_t *special, mobj_t *toucher)
     player_t *player;
     coord_t delta;
     itemtype_t item;
+    enum mobjtouchresult_e touchResult = MTR_UNDEFINED;
 
     DENG_ASSERT(special != 0);
     DENG_ASSERT(toucher != 0);
@@ -969,8 +971,24 @@ void P_TouchSpecialMobj(mobj_t *special, mobj_t *toucher)
 
     player = toucher->player;
 
+    if (Mobj_TouchSpecialScriptedThing(toucher, special, &touchResult))
+    {
+        switch (touchResult)
+        {
+            case MTR_MAKE_DORMANT:
+                item = IT_ITEM_CUSTOM;
+                break;
+
+            case MTR_KEEP:
+                return; // Nothing further to do.
+
+            default:
+                item = IT_NONE;
+                break;
+        }
+    }
     // Identify by sprite.
-    if((item = getItemTypeBySprite(special->sprite)) != IT_NONE)
+    else if ((item = getItemTypeBySprite(special->sprite)) != IT_NONE)
     {
         // In Heretic the number of rounds to give for an ammo type is defined
         // by the 'health' of the mobj.
@@ -1003,11 +1021,13 @@ void P_TouchSpecialMobj(mobj_t *special, mobj_t *toucher)
     case IT_ITEM_TORCH:
     case IT_ITEM_FIREBOMB:
     case IT_ITEM_TELEPORT:
+    case IT_ITEM_CUSTOM:
         setDormantItem(special);
         break;
 
     default:
-        if(gfw_Rule(deathmatch) && !(special->flags & MF_DROPPED))
+        if(touchResult == MTR_HIDE ||
+            (gfw_Rule(deathmatch) && !(special->flags & MF_DROPPED)))
         {
             special->flags &= ~MF_SPECIAL;
             special->flags2 |= MF2_DONTDRAW;
@@ -1019,7 +1039,9 @@ void P_TouchSpecialMobj(mobj_t *special, mobj_t *toucher)
         }
 
         if(!mapSetup)
+        {
             player->bonusCount += BONUSADD;
+        }
         break;
     }
 }